Eight months after opening its digital doors to high school students, Facebook.com is now allowing users in newly-created “work networks” to register on the site with “.com” or “.org” e-mail addresses.

The popular social networking website has certified that over 1,000 “supported” professional networks, from Abercrombie and Fitch to Zions Bancorporation. Employees—including those without undergraduate diplomas—can create profiles and share information.

Members of the professional networks, like all other Facebook members, will appear in search results, but Facebook’s privacy controls limit users to viewing profiles of their friends or members of their networks.

Facebook spokesman Chris R. Hughes ’06 said the expansion came in response to strong user demand.

“Our users tell us day after day, in e-mail after e-mail, that they want to connect with people who don’t have ‘.edu’ e-mail addresses,” said Hughes.

Hughes said Facebook wants to remain relevant to its users who will graduate at the end of this semester and join the workforce.

“We’re committed to growing with our alumni and increasing the site’s utility and availability to them as they leave college,” Founder and CEO Mark E. Zuckerberg, formerly Class of 2006, said in a press release issued yesterday morning.

“We’re trying to open it up so that people don’t have to give up the functionality of Facebook after they leave school,” Hughes said.

Since Zuckerberg launched the site from his dorm room in Kirkland House in early February 2004, the site’s membership has exploded from 650 users in its first week to more than 7.5 million.

Facebook is now the seventh most-visited site on the Internet, according to web traffic tracker comScore Media Metrix.

The social networking site MySpace.com, the second most-trafficked site on the Internet, according to comScore, has over 70 million users.

But Hughes said Facebook doesn’t view MySpace as competition.

“We really think about the two sites differently,” said Hughes. “MySpace seems to be a place where you go to build a profile with colors and music, and connect with people you might not know in real life. Facebook is a place where you go to share information, all of which is based on reality.”

Harvard students had mixed reactions to the news that the ubiquitous site would be casting a wider net.

Manuel Rincon-Cruz ’09 said he liked the collegiate focus of the site.

“I think [work networks] are a bad idea,” he said. “Facebook was meant to be a social network for college students. This will make us more self-conscious online.”

But Paul R. Sullivan ’08 expressed no such concern.

“I feel like it’s a good way for them to expand,” he said. “I wonder if it will ruin productivity in the workplace.”

Indeed Facebook—with such idiosyncratic features as individual message board “wall” postings and “poking”—is well-known as a procrastination tool.

The use of work networks to categorize members is consistent with other recent changes made to the site.

In the past few weeks, Facebook has reconfigured the presentation of users’ friends lists, organizing acquaintances by educational and geographic networks, instead of just by school.

In theory, a registered user could be a member in up to four networks: high school, college, geography, and work.

While it is unlikely that many individuals have passed through high school and college and secured jobs during the two years of Facebook’s existence, Hughes said he expects that “over time, it will be a place where people can coordinate” across multiple networks.

—Staff writer Sam Teller can be reached at steller@fas.harvard.edu.